As computer-based systems, appliances, automated teller machines (ATM), point of sale terminals and the like become more prevalent, the ease of use with regard to the human-machine interface is becoming more important. Such interfaces should operate intuitively and require little or no user training whereby they may be employed by virtually anyone. Conventional human-machine interfaces, such as keyboard, voice, and touch screen, typically require human interactions involving a combination of action, vision and/or sound. For instance, when a user inputs his or her selection(s) over a touch screen, the user needs to look and identify a location on the screen for touching. Also, when a user operates a mouse, the user needs to see the mouse icon on the screen before clicking the mouse.
A problem, however, associated with conventional human-machine interfaces is that, for some situations and/or environments, an operator may not be able to use visual or audio capability to enter an input.
For example, in a healthcare environment, typical medical and health related monitoring/testing equipment used for monitoring and/or testing patients' vital signs notify caretakers such as nurses and doctors when the equipment detects certain predefined less-desirable conditions via visual and/or aural notifications. A typical heart rate monitor, for instance, shows a waveform of heart rate on a display with beeps indicating patient's heart beats. To discern a patient's condition, for example, a caretaker typically needs to look at the heart-rate waveform on the display or listen to the heart-rate beeps or both in order to observe patient's current condition. As such, a drawback associated with a conventional human-machine interface using aural and/or visual notifications is that the interface may be inadequate or inappropriate in some situations, such as in loud or visual cluttered situations, high-stress environments, social events like dinner parties, or entertainment venues such as poker games.